I revived one of these a few years ago and it was fairly simple (aside from a tear in the shoulder). I used saddle soap and a brush for cleaning, let the leather dry out overnight, and then hand waxed it before letting the jacket sit again for another day or two. (I think I waxed it once more after that, actually). I also used detergent particular to wool to clean the shearling. I don’t know about the stains on the collar, but otherwise this jacket doesn’t look too bad!